The present invention relates to wheelchairs. More particularly, the present invention relates to wheelchairs and chassis that are more easily assembled, disassembled, adjusted, and used for mobility of disabled persons.
Conventional wheelchairs provide equipment for use by disabled persons in order to be mobile and to increase the opportunities of disabled persons to participate more fully in daily activities. Conventional wheelchairs are typically manufactured of metal tubes which are cut to length, bent into shape, and welded together to form a tubular frame that supports a seat and back. Wheels connected to the frame provide mobility. Push handles attach to the back of the frame for pushing the wheelchair or controlling its direction of the movement. The purpose of wheelchairs is to provide equipment which solves disability-related problems, so that disabled persons can more easily participate in everyday life activities while minimizing the problems created by the equipment.
Generally, wheelchairs for profoundly immobilized persons are custom-built using specific measurements of the particular person to use the wheelchair. The measurements are used to determine the particular width, depth, and height of the frame, the seat, and the seat back for the wheelchair. Generally, wheelchairs are manufactured in widths ranging from 10 inches to 20 inches, and depths ranging from 12 inches to 18 inches, with varying seat and back heights. Because of the many combinations of sizes, it is expensive to maintain inventories of specific sized component parts. Accordingly, manufacturers of wheelchairs cut elongated tubular members to size based on a customized specification for the particular individual. The tubes are assembled into a frame of a specific design. Production of an individual wheelchair is complex and slowed because custom parts have to be manufactured. Also, due to personalized customization of the dimensions of a wheelchair, it is not practical to maintain inventories of completed frames. Similarly, the large number of variations and combinations prevent retailers of wheelchairs from holding wheelchairs in inventory. Further, there often is a lag time of many weeks between ordering a custom wheelchair and delivery of the wheelchair to the user.
During manufacture, the frame members are typically joined together by welding. The seats, backs, pads, push handles and wheels are then conventionally connected to the frame using clamps, tubular connectors, latches, and bolts with nuts. While these secure the components to the frame, the connectors must be loosened, removed, and re-positioned for adjusting the orientation and position of the components. For aides to wheelchair users who are not skilled in mechanics, operation of these connectors may be difficult, awkward, and frustrating. Also, the connectors must be loosened or removed in order to disassemble the wheelchair for transport in cars.
Further, the tubular frame and the various connectors make conventional wheelchairs difficult to xe2x80x9cgrowxe2x80x9d to accommodate the physical growth of the user. For example, side frames often limit the size of the seat that can be secured to the wheelchair. This presents problems for a child. Changing the size of the seat may require removal and replacement of frame tubes at a manufacturing facility or authorized dealer, which involves re-specification and manufacture of parts, and labor and time to re-work the wheelchair. If a larger seat, and therefore a wider frame, is initially used in a pediatric wheelchair, it may be necessary to position abductors and other support pads laterally inwardly of the sides of the frame. However, a child would have difficulty reaching outwardly to the drive wheels.
Disabled persons who look to wheelchairs for mobility also are dependent on the wheelchair for bodily support. It is important that the wheelchair be lightweight and easily maneuverable, in order to conserve the energy of the person. Also, the seat and back should be easily adjustable to provide proper posture and comfort. Improper seating is not only uncomfortable but may create additional physical problems for the person using the chair. The width, height, depth, and tilt of the seat as well as the width, height, and tilt angle of the back of the seat, affect proper seating. Proper adjustments of the seating variables, together with proper sizing of the wheelchair contributes to a more neutral skeletal alignment and may impede the progression of skeletal deformities and muscle contracture, better manage seating pressures and reducing the potential for pressure sores, improve the seating stability of the occupant, increase sitting tolerance through increased comfort, and decrease fatigue. The tubular frame however often interferes with attachment and adjustment of the pads and abductors which may be critical to properly supporting the user in the wheelchair.
Accordingly, there is a need in the art for improved wheelchairs that are readily assembled, disassembled, adjusted, and used for and by disabled persons. It is to such that the present invention is directed.
The invention provides a caster block that attaches to a frame of a wheelchair for receiving a caster wheel. The caster block comprises a housing having a central bore and a plurality of spaced-apart channels for receiving bolts for attaching the housing to a frame of a wheelchair. A resilient core is received in the central bore and defines an axial bore for receiving a shaft of a caster wheel. The distal ends of the core define recesses which receive bearing races. The caster wheel is rotatably engaged to the caster block by extending the shaft of the caster wheel through the bore of the core and securing the shaft with a nut. In a preferred embodiment, the housing defines at least one channel therethrough which receives a pin having an annular flange extending outwardly in a lower portion. A spring is received on the pin and seated against the flange. A cam lever pivotally connects to an end of the pin. The cam lever, being moved from a first position to a second position, moves the pin within the channel from a recessed position within the housing to an extended position with a portion of the pin extending outwardly of the housing, for engaging a slot in a flange of a caster wheel to lock the wheel in a fixed position.
The present invention provides a wheel lock that attaches to a frame member of a wheelchair for restraining a wheel on the wheelchair from rotation. The wheel lock comprises a bottom plate that has an flange that defines an arcuate cavity on a side edge and a mounting block on an opposing side. The flange and the mounting block extend outwardly in a first direction from the plate to define a recess. The block defines a first tapped bore in an upper surface and a pair of bores in a side surface. A top plate has an edge that matingly engages the arcuate cavity of the top plate and defines a bore that aligns with the tapped bore for receiving a fastener for securing the top plate to the bottom plate and sandwiching the frame member in the recess between the top and the bottom plates. A handle pivotally attaches to one of the bores in the side surface. A lock arm pivotally attaches to the other of the bores in the side surface and is pivotally engaged to an end of the handle. A rigid pin extending laterally from an end of the lock arm. The handle moves between a first position and a second position in order to move the rigid pin from an engaged position against a wheel of a wheelchair to a disengaged position spaced apart from the wheel.
Objects, features, and advantages of the present invention will become apparent from a reading of the following specification, in conjunction with the drawings and the appended claims.